Incheon International Airport (IIA) (Korean: 인천국제공항) (IATA: ICN, ICAO: RKSI) (sometimes referred to as Seoul–Incheon International Airport) is the largest airport in South Korea, the primary airport serving the Seoul Capital Area, and one of the largest and busiest airports in the region. It has been rated as the one of the world's cleanest airports and highly rated international transit airports by Skytrax together with Singapore Changi Airport and Tokyo Haneda Airport.The airport opened on 29 March 2001 to replace the older Gimpo International Airport, which now serves mostly domestic destinations and shuttle flights to several East Asian metropolitan areas including Tokyo, Osaka, Beijing, Hong Kong, Singapore, Shanghai, and Taipei. Incheon International Airport is located west of Incheon's city center, on an artificially created piece of land between Yeongjong and Yongyu Islands. The two islands were originally separated by shallow sea. That area between the two islands was reclaimed for the construction project, effectively connecting the once separate Yeongjong and Yongyu islands. The reclaimed area as well as the two islands are all part of Jung-gu, an administrative district of Incheon. It has 111 boarding gates altogether, with 44 in Terminal 1, 30 in Concourse A (connected to Terminal 1), and 37 in Terminal 2.